Among constituent parts of a washing machine, plastic parts were rarely recycled. In recent years, recycling of plastic parts has been increasing. Regarding how to recycle plastic parts, various methods have been proposed. For example, Japanese Patent Laying-Open No. 2002-240037 proposes a method according to which plastic parts are separately collected and recycled. This method separately collects, from waste products, the same plastic parts having the same composition, crushes and thereafter melts the plastic parts for reuse.
Some recycling plants are recycling washing machines based on this method. A washing machine is manually disassembled into small parts. The separated parts are grouped according to the material of which the parts are made. As for plastic parts, they are grouped according to the type of plastic, and thereafter crushed, washed and formed into pellets. The pellets are used again as materials for producing washing machines. This process is so-called horizontal recycling. Among plastic parts, a water tub is higher in plastic content used therefor. The water tub is also manually detached from the washing machine.
FIG. 23 is a schematic cross-sectional view of a washing machine. A housing 20 has its top where a control panel for example is disposed and its inside where such a main component as a water tub 11 is disposed. In water tub 11, a dehydration tub 12 is disposed. Wash water fills the inside of water tub 11 and clothes to be cleaned are put in dehydration tub 12. Dehydration tub 12 has its bottom where a pulsator 13 is disposed. Pulsator 13 is secured to a rotary shaft 16. Rotary shaft 16 is connected to a reduction-gear unit 14. Water tub 11 has its bottom where a motor 21 is disposed. Rotational motion of motor 21 is transmitted through a belt 24 to gears in reduction-gear unit 14. The rotational motion reduced in speed in reduction-gear unit 14 is transmitted to rotary shaft 16 to rotate pulsator 13 and thereby stir the wash water. The clothes are washed by the stirred flow. In removing water from the clothes, dehydration tub 12 and pulsator 13 rotate together.
While dehydration tub 12 is rotating, water tub 11 does not rotate in a washing process. Reduction-gear unit 14 at the bottom of water tub 11 is secured with clamp bolts 23 to water tub 11. Motor 21 is secured to water tub 11 as well. Around reduction-gear unit 14, a transport angle 22 is disposed. Transport angle 22 is formed for protecting reduction-gear unit 14 and a pulley of reduction-gear unit 14 from shock for example during transport of the washing machine. Transport angle 22 is formed in the shape of a belt to surround reduction-gear unit 14 and is secured to water tub 11 with screws.
When the washing machine is disassembled at a recycling plant, water tub 11 is first removed from housing 20. At this time, dehydration tub 12, pulsator 13, reduction-gear unit 14 and motor 21 for example are still attached to water tub 11. From the water tub in this state, transport angle 22 is detached and thereafter motor 21 and belt 24 are detached. Motor 21 and belt 24 are detached easily by removing screws attached to water tub 11 that are used for securing the motor. Further, clamp bolts 23 are detached. At the bottom of the water tub, in addition to the motor, the reduction-gear unit, a reduction-gear frame and the transport angle, a solenoid valve, wires and hoses for example are disposed. Water tub 11 which is removed from housing 20 and from which at least transport angle 22, motor 21 and belt 24 are thereafter detached and further clamp bolts 23 are detached is herein referred to as “water-tub unit.”
FIG. 24 shows a partial cross-sectional view of water-tub unit 1. Water tub 11 is in the shape of a cylinder with its top opened and is made of plastic. In water tub 11, dehydration tub 12 in the shape of a cylinder with its top opened is formed. Pulsator 13 disposed at the bottom of dehydration tub 12 is planar in shape. In other words, the pulsator formed here is longer in its outer diameter at the bottom as compared with its dimension in the direction of the rotational axis. Rotary shaft 16 includes a dehydration-tub rotary shaft 16a for rotating the dehydration tub and a pulsator rotary shaft 16b for rotating the pulsator. Pulsator rotary shaft 16b is formed in the shape of a solid cylinder and dehydration-tub rotary shaft 16a is formed in the shape of a hollow cylinder to surround the pulsator rotary shaft. Pulsator 13 is secured with a pulsator securing screw 18 to pulsator rotary shaft 16b. Rotary shaft 16 extends through dehydration tub 12 and water tub 11 to be connected to reduction-gear unit 14 disposed at the bottom of water tub 11. At the through portion of dehydration tub 12, a dehydration-tub flange 19 is provided. With a dehydration-tub securing nut 17, dehydration flange 19 and dehydration-tub rotary shaft 16a are secured. Reduction-gear unit 14 includes a plate portion 10. Plate portion 10 is a portion that is secured with the clamp bolts to reduction-gear frame 15 that is secured to the bottom of water tub 11. Reduction-gear frame 15 has a protruding portion formed. Between plate portion 10 and the bottom of water tub 11, a gap is formed. Reduction-gear unit 14 is secured to allow a part thereof to be fit in water tub 11.
In order to disassemble water-tub unit 1, pulsator-securing screw 18 fastened at the top of pulsator 13 is loosened to be detached. After this, pulsator 13 is removed from the inside of dehydration tub 12. Then, dehydration-tub securing nut 17 coupling dehydration tub 12 and dehydration-tub rotary shaft 16a is detached to remove dehydration tub 12 from water tub 11. Depending on the structure of the washing machine, impact force is applied to rotary shaft 16 extending through dehydration tub 12 for detaching dehydration tub 12.
In this way, pulsator 13 and dehydration tub 12 can be separated from the water-tub unit. Since rotary shaft 16 from which dehydration tub 12 is detached is in the shape of a rod, the integrated reduction-gear unit 14 and rotary shaft 16 can be detached from water tub 11 in the downward direction as seen in the drawing. Components mounted on the periphery are thereafter detached so that only water tub 11 is left.
The description above is applied to an example of the washing machine. For disassembling any washing machine of a different structure, it has been necessary as well, because of structural reasons, to completely disassemble the coupling of the pulsator, dehydration tub and rotary shaft and thereby remove first the pulsator and dehydration tub from the water tub. A mechanical disassembling method that differs from the manual one is disclosed for example in Japanese Patent Laying-Open No. 9-300127 according to which mechanical cutting is done in the circumferential direction of the body of the water tub.
The manufacturer and the year of manufacture of washing machines to be recycled differ between the washing machines. If washing machines are different from each other in manufacturer and year of manufacture, they also differ in structure. Among such washing machines, some washing machines may be difficult to manually disassemble. Further, the washing machines may have been used for years that range from a few years to 20 years or longer and thus some washing machines may be difficult to manually disassemble due to the presence of rust or scale formed on the machines. Furthermore, some washing machines may be difficult to easily disassemble due to detergent residues left concentratedly at some portions of the washing machines.
Specifically, the pulsator-securing screw that secures the pulsator to the pulsator rotary shaft is difficult to be reached by a tool and is at the position that is difficult to discern. There was thus such a problem as the requirement of a special tool or longer time taken for fitting a tool in the screw slot. Further, depending on the joint portion between the pulsator and the pulsator rotary shaft or the material of which the bearing portion of the pulsator was made, or the years for which the machine had been used, there was the case where the pulsator could not easily be detached even after the pulsator securing screw was detached, due to the presence of rust or scale. In such a case, the water-tub unit was disassembled, for example, by being thrown against the floor with the opening side facing downward or using a crowbar to break the pulsator itself Thus, in such a case where the pulsator could not easily be detached from the dehydration tub, considerable effort was required.
In addition, since the opposing sides of the dehydration-tub securing nut have such a large dimension as the one ranging from 38 mm to 41 mm, a special tool is required to detach the dehydration-tub securing nut. However, the dehydration-tub securing nut is disposed at the bottom of the dehydration tub, and thus the nut is considerably difficult to be reached by the tool. Thus, there was a resultant problem of low workability in such a state where the dehydration tub was incorporated in the washing machine. Further, there was the case where scale or detergent residue was attached between the rotary shaft and the dehydration-tub flange and thus considerable time and cost were required to remove the dehydration tub from the water tub.
As seen from the above, the manual disassembling required enormous efforts and long time in some cases. When the time consumed was excessively long, the disassembly was abandoned and the washing machine was crushed and discarded without being recycled.
The mechanical cutting method as disclosed in Japanese Patent Laying-Open No. 9-0300127 may be used to remove the water tub without releasing the coupling between the water tub and the rotary shaft. However, the water tub is cut along one plane including the circumferential periphery of the water tub. The method thus allows only 50 to 70% of plastic relative to the total weight of the water tub to be recovered. Another disadvantage is that the larger the water tub in size, the lower the ratio of recovery.
An object of the present invention is to provide an apparatus and a method for disassembling a washing machine that can recover resin from the washing machine at a high recovery ratio. Another object of the present invention is to provide a recycled resin and a resin product that have high quality.